Process of purifying used crank case oil



Sept. 15, 1931. D. s. BELDEN PROCESS OF PURIFYING USED CRANK CASE OIL Filed June 8, 1929 ou/VI TTOe/vey Patented Sept. 15, 1931 UNITED STATES APATENT g OFFICE DANIEL S. BELDEN, OF LOS ANGELES, CALIFORNIA, ASSIGNOR TO FILTROL COMPANY OF CALIFORNIA, OIE LOS AN GIELLFS,4 CALIFORNIA, A CORPORATION OF CALIFORNIA PROCESS F PURIFYING USED CRANK CASE OIL Application led June 8, 1929. Serial No. 869,803.

This invention relates to a process of purifying used crank case oil, particularly from automobiles, so as to remove coloring matter and light hydrocarbons therefrom, and to raise the viscosity and lower the carbon content as measured by the Conradson test. By

means of my process, I am able to accomplish these objects under conditions by which the fire hazard is greatly reduced.

Briefly stated, the process comprises mixing used crank case oil with from 1% to 30% by Weight of a finely divided clay adsorbcnt, preferably of the acid-activated type, distilling the light components from such mixture while assisting the volatilization by bubbling through the mixture a lively stream of inert gas, such as CO2 or nitrogen, stopping the distillation when the light constituents have been removed, and then filtering the residualoil from the Clay.

The accompanying drawing shows in side elevation a more or less diagrammatic view ot an apparatus which is suitable for carrying out this process.

In the drawing, represents combined still and agitating` tank, which may be' heated either by indirect steam or .by an internal electric heater (not shown), and which is provided with a stirrer 11, driving means therefor 12, an oil inlet pipe 13, and an inlet 14 for powdered adsorbent. The tank has a conical bottom 15 from which there is an outlet pipe 16 containing a valve 17. From the top of the vessel a vapor pipe 18, of large diameter, in which there is a valve 19, con-A nects with a water cooled condenser 20.

The tank 10 may be supplied with a stream of an inert gas, such as nitrogen or carbon dioxide, from a cylinder 21, which is the primary source of such gas, or from a gasometer 22, into which the supply of gas circulated through the system may be returned. y A supply pipe 23, into which a cylinder pipe 24 empties, is provided with a check valve 25 near the gasometer and a control valve 26 near the agitating tank. The pipe 23 extends substantially to the bottom of the tank 10 and terminates in a perforated ring 27 adapt-- ed to distribute the gas.

Connected to the outlet pipe 16 is a pump 28, the outlet of which ilows through a cooler 29, which is in turn connected to a ilterpress 30, from whence the liquid is moved to a finished oil storage 31. n

The condenser 20 may be of any efficient type but the kind referred and shown is made up of a plura ity of straight pipes 32 connected by return bends 33 into a zigzag form. Water is allowed to run over the outside of these pipes from a spraying pipe 34. To the end of the condenser, a receiver 35 is connected, this vessel having near its top a gas outlet pipe 36 in which there is a threeway valve 37, the object of which is to provide a path optional either to the atmosphere or to'a pipe 38 which leads back to the gasometer 22 through a compressor 39.

When using my process in the above apparatus, a suitable charge of used crank case oil is first run into the tank`10 through the pipe 13 and heated therein as rapidly as possible to 600 F. While the heating is taking place, powdered adsorbent clay to the amount of 1% to 30% by weight of the 'oil is added through the pipe 14 and incorporated into the oil by means of the agitator 11. As l.the oil Vbegins to approach distilling temperatures,

the valve 19 is opened and the three-way valve 37 is opened to the atmosphere. The valve 26 is opened and a supply of inert gas,l preferably nitrogen, is admitted to the tank 10 from the cylinder 21 through the distributing ring 27. The check valve 25 prevents back pressure upon the gasometer 22 during this operation.

The distillationbeing now in full blast, the three-way valve 37 is turned to connect into the pipe 38 as soon as most of the air has been displaced by gas in the still and condenser. The compressor 39 is then started to return inert gas to the gasometer `22, the gas having been separated within the condenser 20 and the receiver 35 b v the condensatlon of o1l vapors therein. The supply of fresh gas a sight-glass located near the end of the condenser. The'supply of gas is thereupon discontinued and the residue left in the still, to cool it below its dash point, is pumped through the cooler 29 by the pump 28 and into the lter press 30 which is operated to separate the oil and clay. rllhe purified crank case oil may then be pumped to storage and the light condensate from the receiver disposed of as convenient. The apparatus is then ready for another batch of used oilwithout having first to exhaust air from the apparatus.

The degree of purity obtainable in the recovered heavy oil depends upon the amount and quality of the adsorbent used. In using ullers earth, which is permissible, quite heavy dosage is necessary, say 20% or more. I prefer to use acid-activated clay, particularl the kind known as Filtrol, which is ma e by a process somewhat similar to that described in United States Patent No. 1,397,113 to P. W. Prutzman. With this adsorbent as little as 1% by weight will sometimes give good results, although I prefer to use about 5%, and may use as much as 30%.

In the puriiication of used transformer oil,

` the above described process is also very valuable, especially when nitrogen is used as the inert gas. Oils of very high dielectric strength are obtainable since they are produced dry In general, my process is ap-l plicable to the reclamation of mineral lubrieating oils of all descriptions, including turbine oils, and all of these materials, including transformer oil, are to .be understood to be included in the generic term used in some of thlgclaims, namely, used mineral lubricating o1 Reviviied adsorbents may be used instead K' of fresh adsorbents.

' I claim as my invention: Y

1. The process of purifying used lubricating oils which comprises distilling the lighter fractions from a mixture of said used oils and a clay type absorbent, the distillation being assisted by a stream of inertv permanent gas. 2. A process according to claim 1 in which the clay adsorbent is present in amounts f ranging from 1% to 30% by weight of the used oil.

3. A process according to claim 1 in which the clay adsorbenthas previously been acid activated. v

4. A process according to claim 1 in which the used lubricating oil is automobile crank case oil.

5. rlhe process of purifying used lubricating oils which comprises: mixing said oil with a linely divided clay adsorbent and heating the mixture to about 600 F. while passing a lively stream of inert permanent gas therethrough;v distilling from the mixture whatever oils are volatile at theaforesaid temperature; and separating the residual oil from the clay.

6. A process according to claim 5 in which the inert gas is nitrogen.

7. A process according to claim 5 in which the clay adsorbent has-been previously acid activated.'

8. A process according to claim 5 in which i nent gas; distilling the Alighter fractions from said oil and condensing them in an inert atmosphere; separating the condensate .from the inert gas; and returning the latter eventually to a-batch of oil and adsorbent under distillation.l- 11. A process according to claim 10 in which the oil under treatment is automobile crank case oil.

12. A process according to'clairn 10 in which the clay adsorbent has previously been acid activated and is present in the oil in amount not exceeding 30% by weight of the oil nor less than 1%. Y

-13. The process of purifying used lubricating oil which comprises making a mixture of said oil and about 5% by weight of the oil with acid-activated clay heating the mixture to about 600 F. while passing a lively stream of inert permanent gas therethrough;

until the distillation and condensation in an atmosphere of inert gas of so much of the .Y lighter fractions of the oil occurs as will distillunder the aforesaid conditions; cooling the residue of oil and clay; and separating.

the latter from the former.

14. A process according to claim 13 in Which the oil'is automobile crank case oil.

15. A process according to claim 13 in which the inert gas is nitrogen.

16.. A process according to claim 13 in which the distillate is separated from th inert gas and the latter again used for distillation.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 3rd day of June, 1929.

DANIEL S. BELDEN. 

